The present invention relates to a method of forming a metal part and, more particularly, to a method of forming a metal part having an annular flange by a radial extrusion process.
A number of different types of metal parts, such as for example the generally disk-shaped copper contacts which form a part of some semi-conductor devices, require an annular flange. Due to the difficulty in forming the flange structure at the same time that the copper contact is cold worked, such flanges have been formed separately in the past and then brazed to the copper contacts. Although some attempts to form a disk-shaped contact and a radially extending annular flange in a single operation have been attempted in the past, these attempts have been largely unsuccessful. Using prior art techniques, the metal flow has produced large forces on the upper and lower die parts, causing an unacceptably high incidence of die failure. As a consequence, it has not been practical to extrude such annular flange elements due to the friction forces applied to the die surfaces as the metal billet is worked.
Accordingly, it is seen that there is a need for a reliable, economical method for forming an annular flange on a metal part at the same time that the part is cold formed, without stressing the die parts sufficiently to produce die breakage.